The Impact of Anxious Arousal on the Discrimination Between Threat and Safety Cues

The ability to discriminate between sources of threat and safety is critical for adaptive behavior. Falsely attributing threat to perceptually similar, yet benign, environmental cues is known as overgeneralization. While overgeneralization has been demonstrated in individuals with clinical anxiety, we know little about how experimentally induced anxious arousal interacts with conditioned fear learning to influence generalization processes in a healthy population. We used high-density EEG to examine the consequences of an anxious arousal induction on the cortical processing of morphed generalization stimuli that were systematically varied in resemblance to a conditioned threat cue. Following conditioning, participants passively viewed CS+, CS- and five morphed generalization stimuli while EEG was recorded. Specifically, we were interested in the simultaneous capture of steady-state visual evoked potentials (ssVEPs) and late positive potentials (LPPs) in threat-of-electric-shock compared to safe conditions. ssVEPs originate from dipolar sources in early visual cortex and served as an index of the sensory generalization gradient. LPPs represent conglomerate brain response that indexes motivational engagement of subcortical circuitry, allowing us to construct a generalization gradient of motivational significance. We hypothesized that threat-of-shock would promote overgeneralization, showing greater phase synchrony and magnitude of ssVEPs and LPPs, respectively. Results showed a similar magnitude of ssVEPs in both conditions. However, there was a clear difference in motivational value between CS+ and generalization stimuli, as indexed by LPPs, which was enhanced in the threat-of-shock condition. These findings suggest that motivational generalization gradients are more sensitive to the effects of anxious arousal than are gradients in perceptual processing.